PROJECT SUMMARY/ABSTRACT The 1990 Americans with Disabilities Act (ADA), 1999 Olmstead Supreme Court Decision, and ADA Amendments Act of 2008 are supposed to protect people with serious mental illness (SMI) against discrimination by considering institutionalization as the last resort to be used only if integrated community-based services are not a viable alternative. Despite these federal mandates, nursing homes may have replaced state psychiatric hospitals as the default source of care. Nursing homes now serve more adults with mental illnesses than all other healthcare facilities combined. Between 10-25% of nursing home residents are thought to have SMI. Residents with SMI are often younger than the typical resident and require services that nursing homes might not be able to provide. Working-age women with SMI may be a subgroup of nursing home residents particularly vulnerable to this potential warehousing. Knowledge is lacking about the current extent of this potential warehousing of working-age adults with SMI and how trajectories of functioning during the nursing home stay may differ between women and men. We propose using existing data from the 2011-2016 federally mandated, longitudinal Minimum Data Set 3.0 and Certification and Survey Provider Enhanced Reporting files to examine gender differences in an observational longitudinal observational study of adults between the ages of 22 and 64 years with SMI residing in nursing homes. Our specific aims are to: 1) estimate the overall prevalence of narrowly and broadly defined SMI and to describe the length of stay for each psychiatric disorder by gender; 2) examine gender differences in receipt of psychiatric treatment for those with SMI; and 3) examine gender differences in latent variable models of subgroups of functioning among those with SMI and describe relationships between these subgroups, resident and facility characteristics, and disposition status. The work proposed here addresses the 2019-2013 Trans-NIH Strategic Plan for Women?s Health Research strategic goals 1.2: to examine the influence of sex and gender on disease presentation, management, and outcomes; 2.1: to apply advanced study designs for analysis of the influence of gender on health; and 2.3: to leverage existing big data for research on women?s health. This exploratory research will inform efforts to improve the delivery of mental health services to a particularly vulnerable population by illuminating the current care needs of working-age women and men with mental illness.